1. Field of the Invention
The present invention relates to a laminated shim for a disc brake that is disposed between a pad and a pressing member, for pressing a pad against a rotor. The present invention suppresses undesired brake sounds generated between the pressing member and the pad. In particular, the invention relates to a laminated shim for a disc brake having a pad side shim provided at a backside of the backing plate of a pad, and a pressing member side shim disposed between the pad side shim and the pressing member in a laminated manner.
2. Description of the Related Art
Conventionally, various laminated shims have been known, for example, laminated shims are known as described in Japanese Laid-Open Patent Publication No. 2002-318301 and No. 2003-101280.
Japanese Laid-Open Patent Publication No. 2002-318301 teaches a laminated shim that has a pad side shim provided on the backside of the backing plate of a pad, and a pressing member side shim disposed in a laminated manner between the pad side shim and the pressing member (i.e., a piston or caliper claw). The pad side shim has two outer edge pad hooks connected to the backing plate and two inner edge pad hooks. The outer edge pad hooks have a configuration where they extend over the outer peripheral edge of the backing plate extending along the rotor peripheral edge. The outer edge pad hooks are attached to the outer peripheral edge of the backing plate. On the other hand, the inner edge pad hooks have a configuration where they extend over an inner (with regard to the radial direction of the rotor) peripheral edge of the backing plate. The inner peripheral edge extends along an inner rotor circumference near the center of the rotor. The pressing member side shim has one outer edge pressing member hook attached to the backing plate and two inner edge pressing member hooks. The outer edge pressing member hook and the inner edge pressing member hooks of the pressing member side shim have a configuration where they extend over the outer peripheral edge of the backing plate at positions avoiding the outer edge pad hooks and the inner edge pad hooks of the pad side shim. The outer edge pressing member hook and the inner edge pressing member hooks and are attached directly to the peripheral edge of the backing plate.
Japanese Laid-Open Patent Publication No. 2003-101280 teaches a pad side shim that has one outer edge pad hook attached to the backing plate and two inner edge pad hooks. A pressing member side shim has one outer edge pressing member hook attached to the backing plate and two inner edge pressing member hooks. The outer edge pressing member hook and the inner edge pressing member hooks of the pressing member side shim have a configuration where they extend over the peripheral edge of the backing plate at positions avoiding the outer edge pad hooks and the inner edge pad hooks of the pad side shim. The outer edge pressing member hook and the inner edge pressing member hooks are directly attached to the peripheral edge of the backing plate.
Therefore, the pressing member side shims, according to No. 2002-318301 and No. 2003-101280, are configured to hook directly onto the peripheral edge of the backing plate via the outer edge pressing member hook and the inner edge pressing member hooks.
However, one of the objectives of the laminated shim is for the laminated shim to suppress undesired or disturbing sounds that may be made when the pressing member is displaced relative to the surface of the backing plate of the pad. Therefore, the laminated shim desirably has a configuration where the pressing member side shim slides relatively easily along the surface with respect to the pad side shim and the backing plate. However, the pressing member hooks of the pressing member side shims according to No. 2002-318301 and No. 2003-101280 were configured to hook directly onto the peripheral edge of the backing plate. Therefore, the pressing member hooks of the pressing member side shims are not prone to slide with respect to the backing plate due to the frictional resistance arising between the hook and the profile of the peripheral edge of the backing plate. As a result, the pressing member side shims do not easily slide along a surface direction with respect to the pad side shim and the backing plate, resulting in the generation of undesired brake noise.